Electronic drying of foots



June 7, 1949. B. CLAYTON ELECTRONIC DRYING OF FOOTS 2 Sheets-Sheet 1 Filed Oct. 19, 1943 may FARPMSWU gwue/wbom GEM'MME HIGH June 7, 1949. B. CLAYTON 2,472,193

YELECTRONIC DRYING OF FOOTS I I Filed Oct. 19, 1943 2 sheets -sheet z Patented June 7, 1949 UNITED STATES- PATENT OFFICE ELEGTRONIC DRYING F FOOTS Benjamin Clayton, H0uston, Tex., assignor, by

mesne assignments,- to

Benjamin Clayton,

Houston; Tex}, doingbusiness as Refining, Un-

incorporated Application October 19, 1943, Serial No. 506,899

6 Claims.- 1

This invention relates to a drying process and particularly to a process of drying thick, viscous organic materials such as the gums or soapstock separated from glyceride oils during" partial or complete refining steps, the drying operation being carried out by employing high frequency elec-- tric fields.

The gums separated from glyceride oils, such as vegetable oils, in a partial refining or gum precipitating and separating step are'u'sually' in the form of a thick, viscous, gummy material which contains on the average between 35- and 50%- water. These gums particularly from vegetable oils are valuable by-products-of a refining operation as they have a high phosphatid'e content and contain other valuable materials; In order to render them stable against fermentation or bac-" terial growth to produce a phosphatidic material useful for many purposes, or to condition them-for solvent purification steps to recover puified phosphatides and other valuable materials, the'gurn's" must have substantially all of their contained water removed. The phosphatides are deleteri ously afiectecl by high temperatures and as the gums are very poor conductors of heat, it has been found extremely difiicult to dry these materials without thermal degradation thereof. The

only practical processthus far developed has been the stirring of batches of the viscous-material in vacuum chambers with the application-of mod-' erate heat throgh the walls of the container. This" requires large amounts of power and long periods of time, usually many hours or days,- as only contains many valuable ingredients including neutral oil, soap, phosphatides; unsaponifiables, such as sterols, sterol glycosides, etc; This soap stock contains relatively large-amounts of phos-' phatides if no prior partial refining operation has been carried out, which is probably the case in the majority of refining operations. A large portion of these phosphatides, as well as neutr'aloil, are recoverable in undecomposedform by solvent treatments if such treatment is carried out promptly after the soapstockis separated from the oil. Such recovery' operations desirably ill clude a drying step in order to condition thesoap' stock for solvent treatment. Even if no' solverit' treatment of the 'soapstock is contemplated, dryingof the soapstock is desirable in'order to'pr'e vent bacterial growth therein and the dried"soap'-" stock is a valuable detergent material. Again,'t1ie soapstock is a viscous, gummy material in which the more valuable ingredients are damaged by high temperatures. The soapstock' is alSo'aWery poor conductor of heat and no practical process" has been Worked out for the large scale drying of soapstock at low temperaturesso asto not'd'ani-' age the heat-sensitive materials contained therein.

In accordance with the present invention, the fonts from either a partial refining operation or' an alkali refining operation are spread in a layer upon a supporting surface and while in this form are subjected to the action of a high frequency alternating field. By this operation heatis gem erated within the body of the film and-water can'- be rapidly evaporated without increasing the" temperature of the materials being treated to" that which will damage the thermo-sens'itive materials and without the necessity'oftransmitting the heat from the exterior of the materialthrough the material itself into the interior thereof. At?" tempts to rapidly dry these materials even thin films by the application of heat theretothrough heated surfaces has not-been productive of practical results as overheating and destruc tion of valuable constituents has'resulted:

It is, therefore, an object of the present inveh tion to provide an improved p-ro'cessfoi drying foots separated from glyceride oils duringpa'rtial Another object of the invention is to p-rovide' an improved process of drying soapstockfrom the alkali refining of glyceride oils without thermal destruction of the valuable constituents"thereoff.

Another object of the invention is toprovide'?" an improved process of drying at low temperatures, thick, viscous, gummy organic'materials'" containing water.

Another object of the invention is to provide" a process of drying thick, viscous; gummy or: ganic materials containing water, by' subjeeting' such materials in a thin film to a high" frequency alternating field and liberating from'the material water vapors generated in the material.

Another object of the'inventioniistoprovide" an apparatus for subjecting films of thick: viscous, gummy organic material to the'ac'tio'n of a higlf frequency alternating field.

A still further object of the invention is to provide an apparatus for removing water from thick, viscous organic materials by subjecting such materials while in a thin film, to a high frequency alternating field under vacuum conditions.

Other objects and advantages of the invention will appear in the following description of preferred embodiments thereof given in connection with the attached drawing of which Fig. 1 is a somewhat diagrammatic vertical section through an apparatus in accordance with the present invention;

Fig. 2 is a vertical section through the apparatus of Fig. 1 taken on the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 of a modified form of apparatus, and

Fig. 4 is a vertical section taken on the line |4 of Fig. 3.

The apparatus of Figs. 1 and 2 may include a gas-tight casing I which is preferably of cylindrical form made up of cylindrical side wall H and end walls l2 and I3 suitably secured thereto. Ashaft may be journalled in bearings It and I? secured to the end walls l2 and |3, respectively, one end of the shaft l8 extending through a packing gland l9 secured to the bearing It so as to seal the casing in against entrance of air. The shaft It may support a drum 2| having a peripheral surface l and may also have a pulley 22 secured to its end l8 for rotation of the shaft it and drum 2|.

The material operated upon by the present invention is, in general, sufiiciently fiuid to be pumped but will not flow freely through pipes or over a surface in a film or layer. This material may be pumped through a pipe 23 into a supplemental casing 24 having side walls 26 and 27 and end walls 28 and 29 suitably secured to the side wall ll of the main casing H]. The side wall 2% terminates short of the surface of the drum 2| and may have a sliding plate 3| secured thereto for adjustment toward and away from the surface of the drum 2|. The walls 21, 28 and 29 closely engage the surface |5 of the drum 2|, whereas the inner end of the sliding plate 3| is spaced slightly from the surface of the drum 2| so that rotation of the drum 2| in the direction of the arrow 33 causes a layer of material to be formed on and be carried by the said surface l5 of the drum.

An electrode 34 is suitably supported concentric With the drum 2| by suitable insulating supports 36, 31 and 38, the insulating support 3f having a conductor 39 extending therethrough for connection to one terminal of a high frequency generator 4|, the other terminal of the high frequency generator being connected to the casing I0 and through the shaft [4 to the drum 2|. The layer of the material to be treated on the drum 2| is carried through the space between the electrode 3% and the drum 2| and a high frequency alternating field is produced in said space through the film of material by the high frequency generator 4|. The electrical characteristics of the material being treated are such that the water contained therein is selectively heated and heat is generated internally of the layer so that it is not necessary to supply heat to the interior of the layer from a heated surface, the drum 2| and the electrode 34 remaining relatively cool. Preferably a vacuum is maintained in the casing if! by Withdrawal of vapors through the pipe 42 which may be connected to any suitable type of vacuum and condensing system (not shown). Vapors generated by the heat due to the electrostatic field 4 are rapidly liberated from the film of the material on the drum 2| and withdrawn through the pipe 32.

The drum 2| is rotated at a rate so that the material is substantially completely dried before leaving the space between the electrode 3a and the drum 2| and drops from or may be scraped from the surface of the drum 2| by means of a scraper it. The dried material falls into an axially extending opening at in the bottom of the casing It and is received in the housing ii) of a screw conveyor ll secured to the casing id. The screw conveyor ll is preferably of the sealing type provided with a shaft :8 which terminates in an enlarged portion 39 at its discharge end. The dried material, which is, in general, still plastic, is compressed into a thin layer in the space between the enlarged end 39 of the shaft and the conveyor casing it so as to seal the conveyor against entrance of air and provide for removal of the material from the casing Without breaking the vacuum therein.

The modified apparatus shown in Figs. 3 and 4 also includes a gas-tight casing 5% formed of a central cylindrical portion 5| and two end members 52 and 53. A conveyor, including a flexible member 5 3 and a pair of rollers 56 and 5? are mounted within the casing 55 so that the flexible member 5 5 extends longitudinally of the casing and has its upper run 58 positioned adjacent an electrode 59 in the form of a conducting plate, such as a metal plate, suitably supported by insulating members El, 62 and 53 from the casing 5|, the insulating member t2 having a conductor fi l extending therethrough and connected to one terminal of a high frequency generator t6, the other terminal of which is connected to the casing 50.

The material to be treated is delivered into the casing 58 through an auxiliary chamber formed in a casing ti. A pipe 38 feeds the auxiliary casing fill which is shown as a part of the end member 52. The auxiliary easing ill has its bottom portion provided with a plurality of vertically extending holes 69 forming extrusion nozzles for the extrusion of strings of the material upon the upper surface of the upper run 58 of the conveyor To assist in uniformly distributing the material through the nozzles 59 a rotating agitator having arms ll may be mounted in the auxiliary casing El concentric with the lower semi-cylindrical surface of the casing 6i. By pumping the material to be treated under pressure into the casing ti through the pipe 68, thin strings of the material to be treated are uniformly extruded by conjoint action of the pump pressure and the agitator arms H and these strings are laid on the upper run 58 of the conveyor 5d and carried longitudinally thereof through the space between said upper run and the electrode 59.

The high frequency generator 66 produces a high frequency electrostatic field in the said space threading the strings of the material on the conveyor 58, which is of conducting material such as a metal band or screen. The water in the material is rapidly heated by heat generated throughout the layer of material and water vapor is produced and liberated from the layer through the upper exposed surface thereof. Preferably the vapors are withdrawn from the casing 5| through a pipe 12 connected to any suitable condensing and vacuum system (not shown). By the conjoint use of the electrostatic field and vacuum the material being treated is rapidly dried at low 5. temperatures. The dried material falls from the discharge end of the conveyor 54 into an opening 13 in the cylindrical portion of the casing any material tending to adhere to the band 54 being removed therefrom by a scraper 14. As described with considerable detail relative to Figs. 1 and 2, a screw conveyor housing 46 having a screw conveyor 4! thereinmay be employed to discharge dried material from the housing 51 without breaking the vacuum in the housing 5!. The screw conveyor in the casing 46 may be driven from any Su table source of power through the gear or pulley 15. The band or endless conveyor 54 may be driven by means of a shaft 16 supporting the pulley 56 and having one end extending from the housing 5! through a bearing 11 and driven from any suitable source of power through the Pulley 18. Also the agitator 11 may have its shaft 15 extend through one end of the casing so as to be driven by a pulley or sprocket 8| from any suitable source of power. It will, of course, be apparent that the material feeding means of Figs. 1 and 2 can be adapted to the apparatus of Figs. 3 and 4 and that the material feeding means of Figs. 3 and 4 can be employed in the apparatus of Figs. 1 and 2.

By treating gums, soapstock, or other similar viscous, gummy, organic material containing water in a layer or thin film carried by a moving supporting surface, by an electrostatic field in accordance with the present invention, the water may be substantially completely and rapidly removed from the material at low temperatures. N 0 thermal destruction of heat-sensitive materials takes place during the drying operation and the material may be rapidly and quickly dried in a continuous manner as it is received from prior process steps and before chemical reactions or bacterial action have time to go forward. This is of particular importance with respect to gums from partial refining operations and soapstocks from alkali refining operations on glyceride oils. If any of these materials are allowed to stand, they ferment and become putrid resulting in destruction of valuable materials. Furthermore, phosphatides, as well as valuable neutral oil, in soapstock from alkali refining operations are also saponified by exces alkali upon standing to produce les valuable soap and the drying operation of the present invention accomplishes the drying operation before this saponification can take place. while operations under vacuum conditions are preferred, since Vapors are much more rapidly generated and liberated from films or layers of the material being treated and the average temperature of the material may be very much reduced over operations at atmospheric pressure, it is apparent that the air-tight casings described in detail above may be eliminated or opened and the remaining apparatus employed at atmospheric presure if desired. In general, however, operations under vacuum condition produces very much improved results. The frequency of the voltage supplied by the high frequency generators will vary with the material being treated as well as the apparatus employed but will usually range between 10 and 40 megacycles, although radio frequencies between 1 and 100 megacycles are within the contemplation of the present invention.

While I have disclosed the preferred embodiments of my invention it is understood that the details thereof may be varied without departing from the essence of the invention.

6 I claim:

1. The process of drying foots from the refining of glyceride oils, said foots being a thick viscous organic material contaning gums and also containing water dispersed therein, which process comprises, spreading said foots in a thin layer upon a supporting surface, moving said surface having said layer thereon through a drying zone, subjecting said layer while in said zone tothe action of a radio frequency alternating electric field of sufiicient intensity to generate heat in said foots and vaporize said water, maintaining a surface of said layer exposed to a vapor liberating space in said zone to provide for free escape of water vapor from said foots, withdrawing water vapor from said zone at a rate sufficient to produce a vacuum in said zone, and removing the resulting dried foots from said supporting surface and from said zone.

2. The process of drying foots from the refining of glyceride oils, said foots being a thick viscous organic material containing gums and aiso containing water dispersed therein, which process comprises, spreading said foots in a thin layer upon a supporting surface by extruding upon said surface a plurality of parallel strings of said foots, moving said surface having said layer thereon through a drying zone, subjecting said layer while in said zone to the action of a radio frequency alternating electric field of sulficient intensity to generate heat in said foots and vaporize said water, maintaining a surface of said layer exposed to a vapor liberating space in said zone to provide for free escape of water vapor from said foots, withdrawing water vapor from said zone at a rate sufficient to produce a vacuum in said zone, and removing the resulting dried foots from said supporting surface and from said zone.

3. The process of drying gums from the refining of glyceride oils, said gums being a thick viscous organic material containing water dispersed therein, which process comprises, spreading said gums in a thin layer upon a supporting surface, moving said surface having said layer thereon through a drying zone, subjecting said layer while in said zone to the action of a radio frequency alternating electric field of sufficient intensity to generate heat in said gums and vaporize said water, maintaining a surface of said layer exposed to a vapor liberating space in said zone to provide for free escape of water vapor from said gums, withdrawing water vapor from said zone at a rate suificient to produce a vacuum in said zone, and removing the resulting dried gums from said supporting surface and from said zone.

4. The process of drying gums from the refining of glyceride oils, said gums being a thick viscous organic material containing water dispersed therein, which process comprises, spreading said gums in a thin layer upon a supporting surface by extruding upon said surface a plurality of parallel strings of said gums, moving said surface having said layer thereon through a drying zone, subjecting said layer while in said zone to the action of a radio frequency alternating electric field of sufficient intensity to generate heat in said gums and vaporize said water, maintaining a surface of said layer exposed to a vapor liberating space in said zone to provide for free escape of Water vapor from said gums, withdrawing water vapor from said zone at a rate suflicient to produce a vacuum in said zone, and

removing the resulting dried gums from said supporting surface and from said zone.

5. The process of drying soapstock from the refining of glyceride oils, said soapstock being a thick viscous organic material containing gums and also containing water dispersed therein, which process comprises, spreading said soapstock in a thin layer upon a supporting surface, moving said surface having said layer thereon through a drying zone, subjecting said layer while in said Zone to the action of a radio frequency alternating electric field of sufficient intensity to generate heat in said soapstock and vaporize said water, maintaining a surface of said layer exposed to a vapor liberating space in said zone to provide for free escape of water vapor from said soapstock, withdrawing water vapor from said zone at a rate suffi-cient to produce a vacuum in said zone, and removing the resulting dried soapstock from said supporting surface and from said zone.

6. The process of drying soapstock from the refining of glyceride oils, said soapstock being a thick viscous organic material containing gums and also containing water dispersed therein, which process comprises, spreading said soapstock in a thin layer upon a supporting surface by extruding upon said surface a plurality of parallel strings of said soapstock, moving said surface having said layer thereon through a drying zone, subjecting said layer while in said zone to the action of a radio frequency alternating electric field of sufiicient intensity to generate 8 heat in said soapstock and vaporize said water, maintaining a surface of said layer exposed to a vapor liberating space in said zone to provide for free escape of water vapor from said soapstock, withdrawing water vapor from said zone at a rate suificient to produce a vacuum in said zone, and removing the resulting dried soapstock from said supporting surface and from said zone.

BENJAMIN CLAYTON.

REFERENCES CITED The following references are of record in the file of this patent:

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